1. Field of the Invention
The present invention relates to an angular velocity sensor structure, and more particularly to an angular velocity sensor structure which minimizes off-axis sensitivity of an angular velocity sensor to improve the performance of the angular velocity sensor.
Herein, the off-axis sensitivity means the sensitivity by 2-axis components other than an axis component to be needed among 3-axis components (x, y, and z components) of acceleration in vector quantity. For example, if a y-axis component is needed, the off-axis sensitivity comes to the sensitivity by the other x and y-axis components.
2. Description of Related Art
For improvement in performance of an angular velocity sensor, it is very important to eliminate the off-axis sensitivity, i.e. an acceleration component applied in a direction of off-axis. However, it is difficult, in a conventional micro angular velocity sensor having a capacitive sensing structure, to eliminate an acceleration component applied in a direction of off-axis.
As a conventional method for eliminating the off-axis sensitivity, there have been the methods with which the off-axis sensitivity is taken into consideration upon structural-designing of a sensor, upon signal-processing of a sensor using a circuit system, and others.
An acceleration sensor part can be used to measure an acceleration component in a direction of off-axis that is applied in a direction of off-axis to have influence upon the performance of angular velocity. However, this case may cause a problem in that it is impossible to accurately measure the degree of distortion by acceleration applied to an acceleration sensor in a direction of off-axis.
Another method is the case where an acceleration sensor and an angular velocity sensor are provided in a single board. However, in case of vacuum-packaged angular velocity sensor, it is difficult to adapt such a method thereto. It is because if the acceleration sensor provided is a capacitive type, a vacuum-packaging and an atmospheric-packaging are hardly realized at the same time on the same board, and if it is a resonant type, area efficiency is low to increase manufacturing costs.
Therefore, in order to solve above problems, technology is needed which measures the magnitude of acceleration applied to an angular velocity sensor structure in a direction of off-axis and eliminates the same to thereby minimize the off-axis sensitivity of an angular velocity sensor.